This is a set of patches for the lock up of some AM100L and AM1000 systems.
Thanks to UltraScience for this information!

The two software patches are for the AM100L.IDV. Vue AM100L.M68

------------------ Find the line that reads:----------------------

INFI:	DEBUG	F3
	REST	A0-A6,D0-D7		; restore register
	RTE				; return

--------Add the following three lines of changes and comments:--------

INFI:	DEBUG	F3
;  [01/05/84]  Lock-up fix: the data register must be read in order
;  to clear out the 6850's interrupt
	MOVB	P.RCV(A4),D1

	REST	A0-A6,D0-D7		; restore register
	RTE				; return

=============================================================================

------------The next patch is to find the following section:---------------


OUTPR:	DEBUG	F4
	TRMOCP				; get next output character from TRMSER
	TST	D1			; data available?
	BPL	OPRG			;   yes -
	ANDW	#^C<OIP>,@A5		;   no - clear the OIP flag
	MOVB	#CM$16!CM$1STP!CM$TXD!CM$RCE,D7
	CMPW	T.BAU(A5),#2		; is terminal set for 110 baud?
	BNE	10$			;   no -
	MOVB	#CM$16!CM$2STP!CM$TXD!CM$RCE,D7
10$:	MOVB	D7,@A4			; set mode bits
OPRD:	BR	INTX			; return

=============================================================================

-------------Make the following four lines of changes:-----------------

OUTPR:	DEBUG	F4
	TRMOCP				; get next output character from TRMSER
	DEBUG	F5
; [02/10/84] Lock-up fix: the data register must be read in order
; to clear out the 6850's interrupt
	MOVB	P.RCV(A4),D7		;clear out the 6850 interrupt

	TST	D1			; data available?
	BPL	OPRG			;   yes -
	ANDW	#^C<OIP>,@A5		;   no - clear the OIP flag
	MOVB	#CM$16!CM$1STP!CM$TXD!CM$RCE,D7
	CMPW	T.BAU(A5),#2		; is terminal set for 110 baud?
	BNE	10$			;   no -
	MOVB	#CM$16!CM$2STP!CM$TXD!CM$RCE,D7
10$:	MOVB	D7,@A4			; set mode bits
OPRD:	BR	INTX			; return


============================================================================

The final change is a hardware change for those with a Rev. A or Rev. B
AM100L board.

Replace the U42 with an SN74LS373

.